JPH0832014A - Manufacture of ic package - Google Patents

Abstract

PURPOSE:To prevent surface oxidation of a lead frame, when die bonding, wire bonding, and packaging like resin molding are performed. CONSTITUTION:One or more kinds of single substance metal or alloy out of Ta, Zr, Nb, W, Mo and Ti is arranged as getter material in a set space of a metal mold or a space linked with the set space. In this state, inert gas for preventing oxidation is blown into the set space. While the set space is shielded with the gas, die bonding, wire bonding and packaging are performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an IC package.

[0002]

2. Description of the Related Art In the process of manufacturing an IC package,
Generally, a die bonding process for bonding an IC chip to a die pad part of a lead frame, a wire bonding process for wire bonding between the lead part and the IC chip of the lead frame, and a packaging process for packaging the die pad part and the IC chip by molding resin. Contains. Usually, these die bonding process, wire bonding process, and packaging process are performed with the lead frame set in the mold setting space.

By the way, since the lead frame is heated to about 400 ° C. in these steps, generally, in these steps, an inert gas such as argon gas or nitrogen gas for preventing oxidation of the lead frame is applied to the mold. Actually, the above steps are carried out in a state where the gas is blown into the set space and the set space is shielded by these gases.

[0004]

However, even if the inert gas is blown in and shielded as described above, oxygen cannot be completely removed. Therefore, an alloy containing an element such as Cr which is easily oxidized is used. In the case of a lead frame made of, it is inevitable that oxides such as Cr are generated on the surface in these steps.

When an oxide is formed on the surface of the lead frame, the adhesion with the molding material (package material) is impaired when the resin or the like is molded, and the solderability in the wire bonding process is impaired. It causes the problem of being lost.

[0006]

The invention of the present application has been made to solve such a problem. Thus, the invention of the present application includes a die bonding step of bonding a chip to the die pad portion of the lead frame, a wire bonding step between the lead portion of the lead frame and the chip, and a packaging step of packaging the chip and the die pad portion with a packaging material such as resin. In the method for manufacturing an IC package in which the lead frame is set in a mold setting space, any one of Ta, Zr, Nb, W, Mo and Ti is provided in the mold setting space or in a space communicating with the mold setting space. In the state where one or more kinds of single metals or alloys are arranged as a getter material, an inert gas for antioxidant is blown into the set space to shield the set space with the gas, and the die bonding step. , A wire bonding step and a packaging step are performed (claim 1).

Another aspect of the present invention is characterized in that the lead frame is made of an Fe-Cr alloy containing 5 to 10% by weight of Cr (claim 2).

[0008]

As described above, according to the present invention, Ta, Zr,
In a state in which any one of Nb, W, Mo, and Ti, or two or more kinds of single metals or alloys are arranged as a getter material,
Processes such as a die-bonding process, a wire-bonding process, and a packaging process are performed while blowing a shield gas into the set space.
Since the getter material such as r has a function of reacting with oxygen and absorbing it, oxygen can be satisfactorily removed from the set space, and thus oxides are prevented from being generated on the surface of the lead frame in the above process. can do.

As a result, it is possible to prevent the solderability of the lead frame and the adhesiveness with the package material from being hindered by the generation of oxides, and it is possible to achieve good IC.
Can manufacture packages.

Alternatively, even a material containing an element that easily forms an oxide, which has been difficult to use as a lead frame material, can be effectively used as a lead frame material.

According to the present invention, a lead frame made of an alloy containing an element that easily oxidizes as described above, particularly 5 to 10% Cr is used.
It is particularly effective when applied to the manufacture of an IC package using a lead frame made of a Fe-Cr alloy containing wt% (claim 2).

[0012]

EXAMPLES Examples of the present invention will be described in detail below. Set a lead frame made of Fe-7% Cr with Ta as a getter material stuck on the entire inner surface of the mold cavity as a set space, and blow nitrogen gas into the cavity to shield the lead frame. It heat-processed at 400 degreeC for 1 minute.

The oxygen on the surface of the heat-treated lead frame was analyzed by Auger. The results are shown in FIG. 1 in comparison with the case without the getter material. However, in the same analysis, the sputter rate was 4 nm / min.
Is. The vertical axis in FIG. 2 represents the relative intensity of O.

As can be seen from these results, when the getter material is not used, the O concentration in the outer surface layer is about 15% higher than that when the getter material is used.

Next, as a lead frame material, Fe-7% C
Using r and Fe-42% Ni, these were subjected to the same heat treatment as above, and then the wettability of solder was measured. For comparison, the same wetting force was measured for the same heat-treated material without using the getter material.

Here, the wetting force of the solder was measured by melting the solder, immersing the lead frame in the solder, and then measuring the pulling force when the lead frame was pulled up. The result is shown in FIG.

From the results shown in FIG. 2, in the case of Fe-7% Cr,
It can be seen that by using the getter material, a wetting force almost equal to that of Fe-42% Ni can be obtained. In addition, Fe-42
The fact that the presence or absence of getter material has little effect on% Ni is
This is because it does not contain elements such as Cr that easily oxidize.

Although the embodiment of the present invention has been described in detail above, this is merely an example. For example, the present invention is a die bonding process,
It is preferable to apply it to all of the wire bonding process and the packaging process such as resin molding, but in some cases, it may be applied to only one of the processes. Others The present invention can be implemented in variously modified modes without departing from the spirit of the invention.

[Brief description of drawings]

FIG. 1 is a diagram showing an analysis result of O by Auger for confirming the effect of one embodiment of the present invention.

FIG. 2 is a diagram showing a result of a wetting force measurement of a solder of a lead frame performed for confirming an effect of the same example.

Claims (2)

[Claims] 1. A die for a die bonding step of bonding a chip to a die pad portion of a lead frame, a wire bonding step between a lead portion of a lead frame and a chip, and a packaging step of packaging the chip and die pad portion with a packaging material such as resin. In the method for manufacturing an IC package in which the lead frame is set in the set space, any one or two of Ta, Zr, Nb, W, Mo, and Ti in the set space of the mold or the space communicating with the mold is set. The die-bonding step and the wire-bonding step while shielding the set space with the gas by injecting an inert gas for oxidation prevention into the set space while arranging at least one elemental metal or alloy as a getter material. , A method of manufacturing an IC package, characterized by performing a packaging process. 2. A method of manufacturing an IC package, wherein the lead frame is made of a Fe—Cr alloy containing 5 to 10% by weight of Cr.